Buggy code:
public class BaseInterceptor { public static final int DECLINED = - 1 ; public static final int OK = 0 ; protected ContextManager cm ; protected Container ct ; protected Context ctx ; protected int debug = 0 ; protected Log loghelper = Log . getLog ( "org//apache//tomcat//core" , this ) ; public BaseInterceptor ( ) { } public int postReadRequest ( Request request ) { } public int requestMap ( Request request ) { } public int contextMap ( Request rrequest ) { } public int authenticate ( Request request , Response response ) { <START_BUG> return 0 ; <END_BUG> } public int authorize ( Request request , Response response , String [ ] reqRoles ) { } public int preService ( Request request , Response response ) { } public int beforeBody ( Request rrequest , Response response ) { } public ServerSession findSession ( Request req , String reqSessionId , boolean create ) { } public int sessionState ( Request req , ServerSession sess , int newState ) { } public int beforeCommit ( Request request , Response response ) { } public int afterBody ( Request request , Response response ) { } public int postService ( Request request , Response response ) { } public int postRequest ( Request request , Response response ) { } public Object getInfo ( Context ctx , Request request , int id , String key ) { } public int setInfo ( Context ctx , Request request , int id , String key , Object obj ) { } public int handleError ( Request request , Response response , Throwable t ) { } public void addInterceptor ( ContextManager cm , Context ctx , BaseInterceptor i ) throws TomcatException { } public void removeInterceptor ( ContextManager cm , Context ctx , BaseInterceptor i ) throws TomcatException { } public void engineInit ( ContextManager cm ) throws TomcatException { } public void engineShutdown ( ContextManager cm ) throws TomcatException { } public void engineStart ( ContextManager cm ) throws TomcatException { } public void engineStop ( ContextManager cm ) throws TomcatException { } public void engineState ( ContextManager cm , int state ) throws TomcatException { } public void addContext ( ContextManager cm , Context ctx ) throws TomcatException { } public void removeContext ( ContextManager cm , Context ctx ) throws TomcatException { } public void contextInit ( Context ctx ) throws TomcatException { } public void contextShutdown ( Context ctx ) throws TomcatException { } public void contextState ( Context ctx , int newState ) throws TomcatException { } public void reload ( Request req , Context ctx ) throws TomcatException { } public void addContainer ( Container container ) throws TomcatException { } public void removeContainer ( Container container ) throws TomcatException { } public void addSecurityConstraint ( Context ctx , String path , Container ct ) throws TomcatException { } public void addHandler ( Handler h ) throws TomcatException { } public void removeHandler ( Handler h ) throws TomcatException { } public void preServletInit ( Context ctx , Handler sw ) throws TomcatException { } public void postServletInit ( Context ctx , Handler sw ) throws TomcatException { } public void preServletDestroy ( Context ctx , Handler sw ) throws TomcatException { } public void postServletDestroy ( Context ctx , Handler sw ) throws TomcatException { } public final void setDebug ( int d ) { } public final void setContextManager ( ContextManager cm ) { } public final ContextManager getContextManager ( ) { } public void setContext ( Context ctx ) { } public Context getContext ( ) { } public final void log ( String s ) { } public final void log ( String s , Throwable t ) { } public final void log ( String s , int level ) { } public final void log ( String s , Throwable t , int level ) { } public Log getLog ( ) { } public final int getDebug ( ) { } public int registerHooks ( Hooks h , ContextManager cm , Context ctx ) { } }

Fix:
return BaseInterceptor . DECLINED ;